feat: add new session without split option

package.json

@@ -327,6 +327,26 @@
           "type": "boolean",
           "default": false,
           "description": "Automatically reveal a new Pi chat tab when the extension activates. Previously open Pi session tabs are always restored."
+        },
+        "pi-on-code.newChatPanelLocation": {
+          "type": "string",
+          "default": "panel",
+          "enum": ["panel", "splitPanel"],
+          "enumDescriptions": [
+            "Open brand-new Pi chats as tabs in the active editor group without splitting the editor area.",
+            "Open brand-new Pi chats in a new editor group split to the right of the active group."
+          ],
+          "description": "Where brand-new Pi chats open in the editor."
+        },
+        "pi-on-code.chatPanelLocation": {
+          "type": "string",
+          "default": "splitPanel",
+          "enum": ["panel", "splitPanel"],
+          "enumDescriptions": [
+            "Open resumed/forked Pi chats as tabs in the active editor group without splitting the editor area.",
+            "Open resumed/forked Pi chats in a new editor group split to the right of the active group (historical default)."
+          ],
+          "description": "Where resumed and forked Pi chats open in the editor."
         }
       }
     },

src/chat-panel-location.ts

@@ -0,0 +1,17 @@
+/**
+ * Where a newly opened Pi chat panel is placed inside the VS Code window.
+ *
+ * - `"panel"` — the chat opens as a tab in the active editor group; the editor
+ *   area is never split for it.
+ * - `"splitPanel"` — the chat opens in a new editor group split to the right
+ *   of the active group (historical default behavior).
+ */
+export type ChatPanelLocation = "panel" | "splitPanel";
+
+export const DEFAULT_CHAT_PANEL_LOCATION: ChatPanelLocation = "splitPanel";
+
+export function parseChatPanelLocation(raw: unknown): ChatPanelLocation {
+  return raw === "panel" || raw === "splitPanel"
+    ? raw
+    : DEFAULT_CHAT_PANEL_LOCATION;
+}

src/extension.ts

@@ -15,6 +15,7 @@ import {
 } from "./session-sidebar-provider.js";
 import { initLogger, piLog, piWarn } from "./logger.js";
 import { getWorkspaceCwd, getWorkspaceFolders, getWorkspaceRoot, getWorkspaceUri } from "./workspace-context.js";
+import { parseChatPanelLocation } from "./chat-panel-location.js";
 import { registerPhase3Commands } from "./phase3-commands.js";
 import { registerPhase4Commands } from "./phase4-commands.js";
 import type { SessionSummary } from "./types.js";
@@ -1127,7 +1128,7 @@ export async function activate(context: vscode.ExtensionContext): Promise<void>
   ): Promise<void> {
     const newSw = createSessionWindow(context, { path: forkedPath }, false, cwd);
     setActiveSession(newSw);
-    void newSw.webviewPanel.show();
+    void newSw.webviewPanel.show(chatShowColumn("chatPanelLocation"));
     sessionTreeProvider?.refresh();
 
     await initSessionInBackground(context, newSw, { openPath: forkedPath });
@@ -1373,7 +1374,7 @@ export async function activate(context: vscode.ExtensionContext): Promise<void>
           title: summary?.name ?? summary?.firstMessage,
         }, false, summary?.cwd ?? getWorkspaceCwd());
         setActiveSession(sw);
-        await sw.webviewPanel.show();
+        await sw.webviewPanel.show(chatShowColumn("chatPanelLocation"));
         setSessionResultUnread(sw, false);
         sessionTreeProvider?.refresh();
         void initSessionInBackground(context, sw, { openPath: resolved });
@@ -1946,6 +1947,14 @@ async function doUpdatePackage(source: string): Promise<void> {
 
 // ── Add a new session window ──────────────────────────
 
+/** Column for a chat opened under the given location setting key. */
+function chatShowColumn(key: string): vscode.ViewColumn | undefined {
+  const location = parseChatPanelLocation(
+    vscode.workspace.getConfiguration("pi-on-code").get(key),
+  );
+  return location === "panel" ? vscode.ViewColumn.Active : undefined;
+}
+
 function addSession(context: vscode.ExtensionContext, cwd = getWorkspaceCwd()): void {
   const existingDraft = findReusableDraft(sessions.filter((session) => session.cwd === cwd));
   if (existingDraft) {
@@ -1962,7 +1971,7 @@ function addSession(context: vscode.ExtensionContext, cwd = getWorkspaceCwd()):
     void saveOpenSessionPaths();
   };
   setActiveSession(sw);
-  void sw.webviewPanel.show();
+  void sw.webviewPanel.show(chatShowColumn("newChatPanelLocation"));
   void initSessionInBackground(context, sw, { fresh: true });
 }
 

src/test/chat-panel-location.test.ts

@@ -0,0 +1,55 @@
+import * as assert from "node:assert";
+import { readFileSync } from "node:fs";
+import {
+  DEFAULT_CHAT_PANEL_LOCATION,
+  parseChatPanelLocation,
+} from "../chat-panel-location.js";
+
+suite("Chat panel location", () => {
+  test("defaults to splitPanel for missing or invalid values", () => {
+    assert.strictEqual(DEFAULT_CHAT_PANEL_LOCATION, "splitPanel");
+    assert.strictEqual(parseChatPanelLocation(undefined), "splitPanel");
+    assert.strictEqual(parseChatPanelLocation("sidebar-left"), "splitPanel");
+    assert.strictEqual(parseChatPanelLocation(42), "splitPanel");
+  });
+
+  test("accepts the two documented locations", () => {
+    assert.strictEqual(parseChatPanelLocation("panel"), "panel");
+    assert.strictEqual(parseChatPanelLocation("splitPanel"), "splitPanel");
+  });
+
+  test("publishes new (panel) and resume/fork (splitPanel) properties", () => {
+    const manifest = JSON.parse(
+      readFileSync(new URL("../../package.json", import.meta.url), "utf8"),
+    ) as {
+      contributes: {
+        configuration: {
+          properties: Record<string, {
+            default: unknown;
+            enum?: unknown[];
+            enumDescriptions?: unknown[];
+          }>;
+        };
+      };
+    };
+    const newProp = manifest.contributes.configuration.properties["pi-on-code.newChatPanelLocation"];
+    const resumeProp = manifest.contributes.configuration.properties["pi-on-code.chatPanelLocation"];
+    assert.ok(newProp, "pi-on-code.newChatPanelLocation property is missing");
+    assert.strictEqual(newProp.default, "panel");
+    assert.deepStrictEqual(newProp.enum, ["panel", "splitPanel"]);
+    assert.ok(resumeProp, "pi-on-code.chatPanelLocation property is missing");
+    assert.strictEqual(resumeProp.default, "splitPanel");
+    assert.deepStrictEqual(resumeProp.enum, ["panel", "splitPanel"]);
+  });
+
+  test("routes new chats through newChatPanelLocation and resumes/forks through chatPanelLocation", () => {
+    const extension = readFileSync(
+      new URL("../../src/extension.ts", import.meta.url),
+      "utf8",
+    );
+    assert.match(extension, /function chatShowColumn\(key: string\)/);
+    assert.match(extension, /sw\.webviewPanel\.show\(chatShowColumn\("newChatPanelLocation"\)\)/);
+    assert.match(extension, /newSw\.webviewPanel\.show\(chatShowColumn\("chatPanelLocation"\)\)/);
+    assert.match(extension, /await sw\.webviewPanel\.show\(chatShowColumn\("chatPanelLocation"\)\)/);
+  });
+});

src/webview-panel.ts

@@ -98,7 +98,7 @@ export class PiWebviewPanel {
   private _onActivateCb: (() => void) | null = null;
   get isActive(): boolean { return this.panel?.active === true; }
 
-  async show(): Promise<void> {
+  async show(column?: vscode.ViewColumn): Promise<void> {
     if (this.panel) {
       this.panel.reveal();
       // Retained webviews can keep the compositor surface from the size they
@@ -115,7 +115,7 @@ export class PiWebviewPanel {
     this.panel = vscode.window.createWebviewPanel(
       "pi-chat-" + randomId,
       "Pi on Code",
-      vscode.ViewColumn.Two,
+      column ?? vscode.ViewColumn.Two,
       {
         enableScripts: true,
         retainContextWhenHidden: true,